Lyme Disease Tips from your Family Physician

June 7, 2001

As summertime approaches, Minnesotans enjoy more outdoor activities. These outdoor activities bring exposure to ticks that may make our activities less enjoyable. One of the problems Minnesotans face is Lyme Disease. “Lyme Disease is transmitted by ticks and is the most common insect-born illness in the United States,” said Keith Stelter, M.D., family physician for Moose Lake and President of the MAFP. “The disease appears to be on a rise, especially in Minnesota, Wisconsin, and the Northeast United States.” Other tick-born illnesses can be contracted as well through the same tick. At this time, Lyme Disease has gotten most of the publicity, perhaps because a vaccine can be used against it.

People can lessen their chances of obtaining Lyme Disease or any of the tick-born illnesses by using some common sense prevention techniques. Use of insect repellants that contain DEET are effective but usually must be applied frequently throughout the day. All persons should check themselves for ticks after being outdoors. Ticks often attach to parts of the body that are difficult to see and so it may require a buddy system to check for ticks. The deer tick, which carries Lyme Disease and the other diseases, is actually a quite small tick and can be easily missed without careful inspection.

“One good fact to remember is that transmission of Lyme Disease usually requires the tick to be attached 24-48 hours, therefore, checking yourself every night is one of the best prevention techniques,” said Dr. Stelter. Removing the tick should be done carefully and without squeezing. Tweezers can be used to grasp the tick as close to the skin as possible and pulling firmly and steadily straight out without twisting. If you do get a tick bite, both the American Academy of Family Physicians and the American Academy of Pediatrics do not recommend routine use of antibiotics because of the potential for adverse reactions. Also, because only 20-30 percent of deer ticks are infected with Lyme Disease. Therefore, experts have estimated the risk of infection after a bite from a deer tick to be about 1.4 percent.

The diagnosis of Lyme Disease can be fairly straightforward. A circular rash with central clearing at the site of the bite is diagnostic of early Lyme Disease. Children and adults can be easily and very effectively treated at this stage of the disease with little risk of long-term complications. Blood tests for Lyme Disease are somewhat more misleading. Because it is unlikely to be any detectable antibodies at the time of a tick bite, such testing is not recommended. The blood test only turns positive 5-8 weeks after a bite. Other symptoms of Lyme Disease include: fever, joint swelling, and inflammation, flu-like symptoms, and occasionally neurological and cardiac symptoms. These are much less common and usually occur only after a person has had the characteristic rash.

As of this time, the FDA licenses one vaccine for the prevention of Lyme Disease. The vaccine is administered in three doses. The second dose is given one month after the first and the third dose is usually given eleven months later, or one year after the first dose. Dosages should be timed so that the second and third doses are given several weeks before the start of the Lyme season, which usually begins in April or May. Efficacy of the vaccine is 49 percent after two injections and 76 percent after the third injection. It is unknown whether the protective immunity will last a year or more beyond the third dose and some data may suggest that boosters may be necessary. However, further research is needed to find this. The vaccine is only recommended for people ages 15-70 years of age.

Your best source of information on Lyme Disease is to talk to your family doctor about the risks of Lyme Disease in your particular geographic area. Certain areas of Minnesota have virtually no Lyme Disease and others have higher incidences of Lyme Disease.

Lyme Disease cases and deer ticks are not found in every county of Minnesota. Minnesota residents who contracted Lyme Disease between 1993-2000 indicated their likely exposure to deer ticks occurred as follows: The majority of cases (65%) were exposed in these Minnesota counties: Aitkin, Anoka, Cass, Chisago, Crow Wing, Isanti, Kanabec, Mille Lacs, Morrison, Pine Washington; portions of Carlton and southern St. Louis; the eastern-most sections of Houston, Wabasha, and Winona; and northern Ramsey.

Even if one decides to get the vaccine, one should always be cautious around potential tick habitats and when one cannot do that, they should wear clothes that will help shield themselves from ticks. Light-colored long sleeve shirts and long pants, tucking pants into the top of socks or boots helps create a tick barrier and frequent checking for ticks during outdoor activities and especially before bedtime is an excellent idea to help prevent Lyme Disease.

With this knowledge at hand, all Minnesotans should be able to enjoy the wonderful summers we have and participate fully in outdoor activities of their choosing.

The Minnesota Academy of Family Physicians is a professional association of approximately 2,700 family physicians, family medicine residents and medical students organized to assist family physicians in providing quality medical care in Minnesota. The MAFP is the largest medical specialty organization in Minnesota and is a state chapter of the American Academy of Family Physicians, the largest medical specialty organization in the United States with more than 93,000 members.